It has been well known to add an inorganic filler to a thermoplastic resin to improve the latter's dimensional stability.
However, addition of an inorganic filler to an aromatic polycarbonate resin has a serious drawback that the carbonate bond in resin molecular chain is cleaved, inviting large reduction in molecular weight. Molecular weight reduction is particularly large when potassium titanate is added; for example, when potassium titanate is added to an aromatic polycarbonate resin having a viscosity-average molecular weight of 25,000 in an amount of about 10% by weight, the viscosity-average molecular weight decreases to 15,000 or less; thus, it has been impossible to use potassium titanate in an aromatic polycarbonate resin.
As a method for eliminating the drawback, there is known a method of treating an inorganic filler beforehand with a silane coupling agent. Application of this method to potassium titanate, however, has been unable to provide an aromatic polycarbonate resin which can be put in practical use.